Method for servicing air-conditioning  systems, and container for carrying it out

ABSTRACT

The present invention relates to a method for filling a fluid ( 2 ) into the cooling circuit ( 1 ) of air-conditioning systems, in particular into those of motor vehicle air-conditioning systems, in which method the fluid ( 2 ) which is to be filled in is stored at approximately atmospheric pressure in a container ( 3 ), in which method a filling line ( 11 ) is connected to the cooling circuit ( 1 ), which filling line ( 11 ) can be connected by means of an initially closed valve ( 10 ) to a riser line ( 7 ) which dips into the fluid ( 2 ) which is to be filled in, in which method the filling line ( 11 ) is then evacuated, and in which method the valve ( 10 ) is subsequently opened such that the fluid ( 2 ) which is stored under approximately atmospheric pressure rises through the riser line ( 7 ) into the evacuated filling line ( 11 ). The invention is based on the problem of preventing the undesired infiltration of moisture into the cooling circuit ( 1 ). In order to solve the problem, the fluid ( 2 ) which is stored in the container ( 3 ) is closed off in an air-tight fashion by means of a cover ( 4 ) which is in contact with the fluid ( 2 ). The air-tight closure prevents moisture from the atmosphere from infiltrating into the cooling circuit ( 1 ) via the hygroscopic fluid ( 2 ).

The present invention relates to a method for filling a fluid into the cooling circuit of air-conditioning systems, in accordance with the preamble of claim 1. Furthermore, the invention relates to the use of a container when filling a fluid into the cooling circuit on an air-conditioning systems in accordance with the preamble of claim 5.

Method, container, and its use are known from U.S. Pat. No. 6,595,039 B2.

In the cooling circuit of an air-conditioning system, not only the coolant but also refrigerator oil, which primarily serves to lubricate the compressor, circulates as a working medium. The cooling circuit of a motor vehicle air-conditioning system, in particular, must be checked for leaks from time to time, since escaping coolant represents an environmental problem and reduces the performance capacity of the system. During the search for leaks, so-called air-conditioning service devices are used, which are connected to the cooling circuit with a filling line. The air-conditioning service devices are equipped with a vacuum pump, by means of which the connected filling line is evacuated. The connection between filling line and cooling circuit is, of course, closed while the vacuum is being generated, in order not to draw the coolant into the vacuum pump. The filling line is connected with a riser line, by way of a valve that is closed, at first; the riser line dips into an open container in which a liquid testing agent (fluid) is stored. This fluid is refrigerator oil into which a UV leak-seeking additive has been mixed. The UV leak-seeking additive is understood to be a liquid or solid pigment that fluoresces when excited by UV radiation.

After the filling line has been evacuated, the valve to the riser line is opened, so that a continuous connection between the riser line and the filling line is formed. The air column that bears on the fluid drives the fluid through the riser line into the filling line, so that the latter is completely filled with the liquid testing agent. Depending on the pressure conditions prevailing at the filling location of the cooling circuit, the fluid evaporates, it can be poured in, or it must be pumped into the cooling circuit by means of external pressure application.

A device for pumping the fluid into the cooling circuit, which is under pressure, is shown by U.S. Pat. No. 6,155,066.

Once it has arrived in the cooling circuit, the UV leak-seeking additive is pressed against the wall by the internal pressure. It exits at leak points, and is traced using a UV lamp, with which the cooling circuit is lit up during the inspection. The testing agent remains in the cooling circuit if it does not escape.

A problem that has not been taken into consideration in the state of the art consists in the fact that the fluid is extremely hygroscopic. For this reason, water from the moist ambient air collects in it, while the testing agent is being stored in the container. Thus, moisture is introduced into the cooling circuit when the fluid is filled in. This is undesirable, since this can result in icing within the system, or corrosion in the lines.

The present invention is therefore based on the task of further developing a method for filling a fluid into the cooling circuit of air-conditioning systems, in such a manner that the undesirable introduction of moisture from the air, by way of the hygroscopic fluid, is avoided.

This task is accomplished in that the fluid stored in the container is sealed, in air-tight manner, using a lid that stands in contact with the fluid.

The basic idea of the present invention consists in storing the fluid in air-tight manner. In order to allow rising of the fluid through the riser line into the evacuated filling line, however, it is necessary for at least atmospheric pressure to be applied to the container. For this reason, a lid is provided that transfers the atmospheric pressure to the fluid. It must therefore stand in contact with the fluid, and furthermore must be movable; the lid can also be configured as a membrane.

Preferably, the lid floats on the fluid and is sealed, with regard to the wall of the container, by means of a circumferential seal. The lid that floats on the fluid transfers the air pressure column directly to the fluid. The hydrostatic pressure in the fluid is additionally increased by the inherent weight of the lid. To this extent, the fluid is not stored precisely, but rather only approximately, under atmospheric pressure, namely at a slightly higher pressure. The circumferential seal is not supposed to exert overly great friction forces, so that the lid can follow the dropping fluid level.

Preferably, the lid is provided with an opening through which the riser line extends. In this manner, the lid is guided along the riser line. Of course, the opening must be sealed on the riser line, so that no moisture in the air gets to the fluid through the opening.

The present invention will now be explained using a fundamental diagram and an exemplary embodiment. For this purpose, the figures show:

FIG. 1: fundamental diagram of filling method and container:

FIG. 2: exemplary embodiment of container.

What must be done is to service the cooling circuit 1 of a motor vehicle air-conditioning system. Within the framework of this action, a mixture of refrigerator oil and UV leak-seeking additive, referred to in short as “fluid” 2, must be filled into the cooling circuit 1.

The fluid 2 is situated in a container 3 that is open towards the top, in which a lid 4 is guided to move. The lid 4 floats on the fluid 2 and therefore follows its level. The lid 4 is provided with a circumferential seal 5, which seals it with regard to the wall of the container 3. In the center, the lid 4 is provided with an opening 6, through which a riser line 7 penetrates the lid 4 and is immersed in the fluid 2. The opening 6 is sealed with a seal 8, so that the fluid 2 as a whole is enclosed in the container 3 in air-tight manner.

The air column 9 rests on the lid 4 and fluid 2, so that the fluid 2 is stored in the container 3 approximately under atmospheric pressure. The quotient of the weight force and area of the lid 4 is added to the atmospheric pressure; the hydrostatic pressure in the fluid 2 is therefore slightly above atmospheric pressure at the level height.

The riser line 7 is connected with a filling line 11 by way of a valve 10. The filling line 11 in turn is connected with the cooling circuit 1 by way of a second valve 12, and with a vacuum pump 14 by way of a third valve 13.

At first, all the valves 10, 12, and 13 are closed; in particular, the valve 10 on the riser line 7 must remain closed, so that the hygroscopic fluid 2 does not draw any moisture. After the filling line 11 is connected with the cooling circuit 1, the valve 13 is opened and the vacuum pump 14 is turned on. The latter evacuates the filling line 11. After the vacuum has been produced, the valve 13 is closed, and the first valve 10 is opened. The air column 9 now presses the fluid 2 through the riser line 7 into the filling line 11. As soon as the latter is filled, the valve 10 is closed again, and the valve 12 is opened. Now the fluid 2 situated in the filling line 11 can flow into the filling circuit 1; if necessary, a piston, not shown here, is required, which presses the fluid in. After filling, the valve 12 is closed again.

Container 3, riser line 7, valve 10, filling line 11, valve 13, and vacuum pump 14 are combined into an air-conditioning service device 15. This can now be connected with another air-conditioning system.

FIG. 2 shows an exemplary embodiment of the container 3. It is closed off, towards the top, with a closure 16, in order to protect the movable lid 4. In order to guarantee that proper functioning is fulfilled, the closure 16 is provided with a passage bore 17. Because of the vacuum in the filling line, it is sufficient if the riser line 7—as shown in FIG. 2—comes into contact with the surface of the fluid 2 and thus is immersed only minimally. The riser line 7 can optionally be configured as a flexible hose or as a rigid pipe. 

1. Method for filling a fluid (2) into the cooling circuit (1) of an air-conditioning system, particularly into that of a motor vehicle air-conditioning system, a) in which the fluid (2) to be filled in is stored in a container (3) at approximately atmospheric pressure, whereby the fluid (2) stored in the container (3) is closed off, in air-tight manner, using a lid (4) that stands in contact with the fluid (2), b) in which a filling line (11) is connected with the cooling circuit (1), which line can be connected with a riser line (7) that is immersed in the fluid (2) to be filled in, by way of a valve (10) that is closed, at first, c) in which the filling line (11) is then evacuated, d) and in which subsequently, the valve (10) is opened, so that the fluid (2), which is stored at approximately atmospheric pressure, rises into the evacuated filling line (11) through the riser line (7).
 2. Method according to claim 1, wherein the lid (4) floats on the fluid (2) and is sealed, with regard to the wall of the container (3), by means of a circumferential seal (5).
 3. Method according to claim 2, wherein the lid (4) is provided with an opening (6) through which the riser line (7) extends.
 4. Method according to claim 1, wherein the fluid (2) is refrigerator oil, UV leak-seeking additive, or a mixture of the two.
 5. Use of a container (3) when filling a fluid (2) into the cooling circuit (1) of an air-conditioning system, particularly a motor vehicle air-conditioning system, whereby the fluid (2) to be filled in is stored in the container (3) at approximately atmospheric pressure, and whereby the container (3) is closed off, in air-tight manner, by a lid (4) that stands in contact with the fluid (2), whereby the lid (4) is sealed, with regard to the wall of the container (3), by means of a circumferential seal (5), wherein a riser line (7) for removing the fluid (2) out of the container (3) is immersed in the fluid (2), and that the lid (4) floats on the fluid (2).
 6. (canceled)
 7. Use of a container according to claim 5, wherein the lid (4) is provided with an opening (6) through which the riser line (7) extends.
 8. Use of a container according to claim 5, wherein the fluid (2) is refrigerator oil, UV leak-seeking additive, or a mixture of the two. 